(239-а)×86=8772, 21с-7с=154

Question

(239-а)×86=8772, 21с-7с=154

Answer 1

(239-а)×86=8772
239-а=8772:86
239-а=102
а=239-102
а=137

21с-7с=154
14с=154
с=154:14
с=11

Answer 2

1) 239-а=8772:86
239-а=102
а=239:102
а=2
2) 14с=154
с=154:14
с=11